1. Technical Field
The present invention relates to a vehicle seat belt webbing retractor, and, in particular, to a retractor including a primary belt locking mechanism for blocking withdrawal of belt webbing from the retractor and a secondary belt locking mechanism which is actuatable in the event the primary belt locking mechanism does not block withdrawal of belt webbing from the retractor.
2. Description of the Prior Art
A known seat belt system to restrain a vehicle occupant includes a length of belt webbing wound on a spool of a seat belt webbing retractor. The belt webbing is extensible about a vehicle occupant to restrain the occupant. The retractor includes a belt webbing clamp mechanism which is actuatable, in the event of a vehicle emergency, to block withdrawal of belt webbing from the retractor. If the belt webbing clamp mechanism does not block withdrawal of the belt webbing from the retractor, the spool shifts radially, and ratchet teeth on the spool engage a member on the retractor to block further rotation of the spool. After termination of the vehicle emergency, the spool shifts back to its original position and is thereafter rotatable as it was before the vehicle emergency. It would be desirable to know when this shifting of the spool has occurred so that the retractor can be checked for damage.